5th Gear Grind at Freeway Speeds?

[Muaddib]

They need to replace the shitty brass synchros with carbon fiber synchros.

[Paewrblue]

I have this issue too when I drive around 100km/h in 6th and needs to downshift to 5th to overtake it would grind. But, if I drive at the lower speed such as 70-80km/h in 6th and downshift to 5th it wouldn't grind. I also do rev-matching or even heel and toe to make shifting goes smoothly still it doesn't work. This problem occured to me a week ago, after getting my 10,000km maintenance at the local Subaru Dealer.

I guess, I should take my car to do some inspection for this issue before it leads to another big problem.

Is there any update to fix this issue yet ?

[EL_to_TBD]

That is exactly the problem I had on my first tranny.
My second one has 2nd and 3rd grind now so I will be trying Pentosin 75W-80 once I have dealer approval, and then if that doesn't work it will be time for another replacement.

As far as I know, there is still no fix (see links below).
Take yours in and get them to check the tranny fluid - it will have metal shavings in it and that will be the justification they need to replace it.
Good luck!

http://www.ft86club.com/forums/showthread.php?t=16604
http://www.ft86club.com/forums/showthread.php?t=61827
http://www.ft86club.com/forums/showthread.php?t=8437
http://www.ft86club.com/forums/showthread.php?t=31929

[Rocket.BRZ]

any update on this? 6th gear on my car is starting to grind with 15,000 miles on it. Aftermarket clutch, Aftermarket fluid, short shifter, and bushing. I have to many modifications to take it back to the dealer for this kind of problem. Is it possible that I could buy the synchros and replace them myself?

[sierra]

Originally Posted by Rocket.BRZ

any update on this? 6th gear on my car is starting to grind with 15,000 miles on it. Aftermarket clutch, Aftermarket fluid, short shifter, and bushing. I have to many modifications to take it back to the dealer for this kind of problem. Is it possible that I could buy the synchros and replace them myself?

The danger might be that once the symptoms appear the oil is already contaminated and other damage has started?
With mine it was a 5th gear grind and they didn't hesitate to replace the gearbox under warranty, soon after those symptoms appeared. Less miles than yours, about 9000.
If replacing the syncros was a fix why would they fit a new box?

[Rocket.BRZ]

Originally Posted by sierra

The danger might be that once the symptoms appear the oil is already contaminated and other damage has started?
With mine it was a 5th gear grind and they didn't hesitate to replace the gearbox under warranty, soon after those symptoms appeared. Less miles than yours, about 9000.
If replacing the syncros was a fix why would they fit a new box?

My guess is that they wanted to take the gearbox back for analysis. I wouldn't think a dealer is going to tear down and replace a synchro right in the shop for time and reliability sake. Quite possible damage may have been done but I don't believe subaru is going to take back my gearbox based on my circumstances.

[sierra]

Originally Posted by Rocket.BRZ

My guess is that they wanted to take the gearbox back for analysis. I wouldn't think a dealer is going to tear down and replace a synchro right in the shop for time and reliability sake. Quite possible damage may have been done but I don't believe subaru is going to take back my gearbox based on my circumstances.

That's exactly what they did. The gearbox was shipped back to Japan.
I like to think they have modified future gearboxes based on that policy, which might mean any spares could be to a different spec and could upgrade repairs?
I would drop the oil first, to see what's in it, if anything?

[Rocket.BRZ]

Originally Posted by sierra

That's exactly what they did. The gearbox was shipped back to Japan.
I like to think they have modified future gearboxes based on that policy, which might mean any spares could be to a different spec and could upgrade repairs?
I would drop the oil first, to see what's in it, if anything?

Ok ill order some new fluid. Drain the fluid and replace it. I know the first time I drained the transmission it had a small amount of metal shavings but that was from break in I would assume. If it does contain metal what should I do. Subaru won't take it back.

[sierra]

Originally Posted by Rocket.BRZ

Ok ill order some new fluid. Drain the fluid and replace it. I know the first time I drained the transmission it had a small amount of metal shavings but that was from break in I would assume. If it does contain metal what should I do. Subaru won't take it back.

I would stop driving it and get a good transmission specialist to pull the box out and strip it, based on the symptoms, to see what they find. It's a conventional box with old fashioned brass or phosphor bronze syncros I think? You might be able to upgrade them with something better?

Are you sure it's nothing to do with the clutch not releasing fully?

[Rocket.BRZ]

Originally Posted by sierra

I would stop driving it and get a good transmission specialist to pull the box out and strip it, based on the symptoms, to see what they find. It's a conventional box with old fashioned brass or phosphor bronze syncros I think? You might be able to upgrade them with something better?

Are you sure it's nothing to do with the clutch not releasing fully?

If it was the clutch I would think it would grind in every gear not just 5th

[Rocket.BRZ]

Hey guys I wanted to update that I switch from pentosin to redline with 1 quart of shockproof. 5th gear grind is completely gone and its shifts like butter.

[sierra]

Originally Posted by Rocket.BRZ

Hey guys I wanted to update that I switch from pentosin to redline with 1 quart of shockproof. 5th gear grind is completely gone and its shifts like butter.

Was it 5th or 6th gear?
You might pass that on to Toyota and Subaru to try instead of changing gearboxes.

[Rocket.BRZ]

Originally Posted by sierra

Was it 5th or 6th gear?
You might pass that on to Toyota and Subaru to try instead of changing gearboxes.

5th gear. I have an aftermarket clutch and my car is supercharged so I don't believe they will work on it.

[sierra]

Originally Posted by Rocket.BRZ

5th gear. I have an aftermarket clutch and my car is supercharged so I don't believe they will work on it.

I meant just for their information, as something that worked for you and could work for them.